The number and location of valence electrons determine an element's position on the periodic table and its chemistry.
Elements in any given group on the periodic table have the same number of valence electrons.
The number and location of valence electrons determine the chemistry of an element.
Elements within a group have similar physical and chemical properties.
Representative elements display the range of possible valence electrons from one in group 1A
and 8 in group 8A
The valence electrons of representative elements are in s or p orbitals
Properties within a group are not identical because members have different numbers of inner electrons
While elements of a group of have the same number of valence electrons, their number of non-valenceelectrons differs
As new levels of electrons are added, the atomic radius increases and the shielding effect increases, thus ionization energy decreases
Lower ionization energy makes it easier for an element to lose electrons
Metals
-as a group, tend to lose electrons
-the lower the ionization energy, the more reactive the metal
-reactivity increases as atomic number increases
Non-metals
-tend to gain electrons
-the higher the ionization energy, the more reactive the nonmetal
-reactivity decreases as the atomic number increases DIAGONAL RELATIONSHIPS:
· elements in period 2 have more in common with the period-3 element in the next group than the period-3 element in their own group
· don’t behave as predicted by their locations on the periodic table
The representative elements in group 1A through 8A have only s and p block electrons
each group of the representative elements have the same number of valence electrons
the representative elements show the range of the number of valence electrons
the valence electrons are in s or p orbitals
Properties of s-block elements
property of alkali metals (group IA)
explanation
metallic
very low ionization energy; the electron sea model works well for alkali metals
soft
ns1 valence configuration contributes just 1 electron to the electron sea. The sea is weak. Metal cations aren't tightly bound and it's easy to slide them past each other.
low densities
Alkali metals have the largest radii and lowest atomic weight in each period. Low mass in high volume = low density.
highly reactive
very low ionization energies make alkali metals good electron donors in redox reactions.
-lithium:-lightest alkali metal:- found in water, rock, and soil:- least reactive of alkali metals -compounds less likely to dissolve in water -atomic radius- 152pm: ionic radius-76pm- related most to magnesium -sodium & potassium:- most abundant alkali metals -potassium more reactive than sodium- potassium ions are the most common positive ions within a cell- sodium ions are the most common positive ions in the fluid around the cell -other alkali metals: -the most reactive alkali metals-rubidium, cesium, and francium-rubidium has a melting point of 40 degrees C, exposed to air will burst into flames-francium is the most reactive alkali metal is a rare radioactive element
the alkaline earth metals (Group IIA)
soft, but harder than alkali metals
ns2 valence configuration =more electrons in the sea= more tightly bound metal cations
reactive, but not as reactive as alkali metals
ionization energies are not as low as alkali metals
salts less soluble than those of the alkali metals
higher cation charge concentrated on smaller cations makes it hard to pull apart ionic lattices
(information from General Chemistry Online)
HYDROGEN
- Henry Cavendish discovered hydrogen in 1766
- In 1783, Antoine Lavoisier named hydrogen for the water that forms when hydrogen and oxygen combine
- has one valence electron
- DOES NOT mean that hydrogen has same properties as metals in group 1A, hydrogen shares many properties with nonmetals in group 7A
- hydrogen has both metallic and nonmetallic properties and it is not considered part of either group
- when hydrogen atom acts like a nonmetal, it gains an electron and achieves stable electron configuration of helium
- when hydrogen reacts with nonmetal (i.e. oxygen) it acts like a metal and loses it’s single electron and forms a hydrogen ion
MAGNESIUM
- abundant element
- can be formed into any shape
- oxide of magnesium has such a high melting point that it is used to line furnaces
- plants can’t function with out magnesium because each chlorophyll molecule contains a magnesium ion (chlorophyll contains pigments/color of the plant)
- when large quantities of calcium and magnesium ions are found in the water supply, it’s called “hard water”.
- Magnesium ions can form deposits that can potentially clog pipes, water heaters, and appliances (i.e. steam irons)
BERYLLIUM
-Has 2 valence electrons
-Combined with aluminum, silicon, and oxygen in a material called beryl
-Has a diagonal relationship with aluminum; similar chemical properties
-used to moderate neutrons in nuclear reactors
CALCIUM
-Has 2 valence electrons
-Combined with carbon and oxygen in calcium carbonate
-This compound is the main ingredient in rocks such as limestone, chalk, and marble.
7.2
The most abundant elements in Earth's crust, silicon and oxygen, are usually found in silica, which can be melted and rapidly cooled to form glass.
Lead, which is still used in storage batteries, was used in pipes, paint, and gasoline until people realized the danger of lead poisoning.
Phosphates in fertilizers and cleaning products can harm the environment.
cleaning8-25.jpg
Graph - Production / consumption - Phosphate fertilizers
The Nitrogen Group- Group 5A
Nitrogen, Phosphorus, Arsenic, Antimony, Bismuth
Each have five valence electrons, and display a wide variety of physical and chemical properties.
Nitrogen gas is colorless, odorless, and relatively unreactive. About 78% of the earth's atmosphere is nitrogen. The major industrial use of hydrogen is in the production of the nitrogen compound ammonia, which is a colorless gas with an irritating odor. Ammonia is used in cleaning products, and can be used as a source of nitrogen for plants. About 25% of ammonia is converted into nitric acid, which is used to produce explosives, dyes and solid fertilizers. Artists use nitric acid to etch designs into metal plates. Some nitrogen compounds are extremely unstable.
7.3 Properties of d-block and f-block Element
An element is considered "d" or "f" when its d or f orbital has been filled. (Transitional [d] and Inner-transitional [f] )
D-block transitional metals and f-block are more similiar across a period than s-block and p-block elements. This is because they have more "basic roots" in common. All have the "s" and "p" orbital filled, resulting in more common bases.
As you move across a period, (horizontal), the elements become harder, and require higher temperatures to melt and boil. Until you reach chromium. Chromium is the hardest. As you move right of chromium the electrons begin to pair up instead of standing alone. This makes them softer as you degrade. Zinc is the softest. (Because its "3d" orbitals are completely filled.)
Electrons in d sublevels can absorb visible light of specific wavelengths. This results in colorful properties.
Ferromagnetic are permanently aligned in the direction of a magnetic field because all ions are aligned in the same direction. Which means they have no opposite attractions to cancel out. (Iron, cobalt and nickel.)
Strategic metals are metals that are essential for industry and national security, but for which a nation has little or no domestic supply. This list includes, but is not limited to platinum, chromium, cobalt, maganese, and tungsten. These transitional-strategic metals are rare because they are found combined in nature with other elements and require extensive procedures to extract them to their pure form.
Lanthanide metals have "silvery" properties.
7.2 Properties of p-Block Elements
P-block elements include metals, metalloids, nonmetals, and inert gases.
Aluminum is the most abundant metal in earth's crust. Much more energy is needed to extract aluminum from its ore than recycle aluminum.
Because a carbon atom can join with up to four other carbon atoms, carbon forms millions of organic compounds.
Chapter 7
7.1 Properties of s-Block Elements
The number and location of valence electrons determine an element's position on the periodic table and its chemistry.
Elements in any given group on the periodic table have the same number of valence electrons.
The number and location of valence electrons determine the chemistry of an element.
Elements within a group have similar physical and chemical properties.
Representative elements display the range of possible valence electrons from one in group 1A
and 8 in group 8A
The valence electrons of representative elements are in s or p orbitals
Properties within a group are not identical because members have different numbers of inner electrons- While elements of a group of have the same number of valence electrons, their number of non-valence electrons differs
- As new levels of electrons are added, the atomic radius increases and the shielding effect increases, thus ionization energy decreases
- Lower ionization energy makes it easier for an element to lose electrons
- Metals
-as a group, tend to lose electrons-the lower the ionization energy, the more reactive the metal
-reactivity increases as atomic number increases
- Non-metals
-tend to gain electrons-the higher the ionization energy, the more reactive the nonmetal
-reactivity decreases as the atomic number increases
DIAGONAL RELATIONSHIPS:
· elements in period 2 have more in common with the period-3 element in the next group than the period-3 element in their own group
· don’t behave as predicted by their locations on the periodic table
The representative elements in group 1A through 8A have only s and p block electrons
- each group of the representative elements have the same number of valence electrons
- the representative elements show the range of the number of valence electrons
- the valence electrons are in s or p orbitals
Properties of s-block elements- the alkaline earth metals (Group IIA)
- soft, but harder than alkali metals
- ns2 valence configuration =more electrons in the sea= more tightly bound metal cations
- reactive, but not as reactive as alkali metals
- ionization energies are not as low as alkali metals
- salts less soluble than those of the alkali metals
- higher cation charge concentrated on smaller cations makes it hard to pull apart ionic lattices
(information from General Chemistry Online)HYDROGEN
- Henry Cavendish discovered hydrogen in 1766
- In 1783, Antoine Lavoisier named hydrogen for the water that forms when hydrogen and oxygen combine
- has one valence electron
- DOES NOT mean that hydrogen has same properties as metals in group 1A, hydrogen shares many properties with nonmetals in group 7A
- hydrogen has both metallic and nonmetallic properties and it is not considered part of either group
- when hydrogen atom acts like a nonmetal, it gains an electron and achieves stable electron configuration of helium
- when hydrogen reacts with nonmetal (i.e. oxygen) it acts like a metal and loses it’s single electron and forms a hydrogen ion
MAGNESIUM
- abundant element
- can be formed into any shape
- oxide of magnesium has such a high melting point that it is used to line furnaces
- plants can’t function with out magnesium because each chlorophyll molecule contains a magnesium ion (chlorophyll contains pigments/color of the plant)
- when large quantities of calcium and magnesium ions are found in the water supply, it’s called “hard water”.
- Magnesium ions can form deposits that can potentially clog pipes, water heaters, and appliances (i.e. steam irons)
BERYLLIUM
-Has 2 valence electrons
-Combined with aluminum, silicon, and oxygen in a material called beryl
-Has a diagonal relationship with aluminum; similar chemical properties
-used to moderate neutrons in nuclear reactors
CALCIUM
-Has 2 valence electrons
-Combined with carbon and oxygen in calcium carbonate
-This compound is the main ingredient in rocks such as limestone, chalk, and marble.
7.2
The most abundant elements in Earth's crust, silicon and oxygen, are usually found in silica, which can be melted and rapidly cooled to form glass.
Lead, which is still used in storage batteries, was used in pipes, paint, and gasoline until people realized the danger of lead poisoning.
Phosphates in fertilizers and cleaning products can harm the environment.
The Nitrogen Group- Group 5A
Nitrogen, Phosphorus, Arsenic, Antimony, Bismuth
Each have five valence electrons, and display a wide variety of physical and chemical properties.
Nitrogen gas is colorless, odorless, and relatively unreactive. About 78% of the earth's atmosphere is nitrogen. The major industrial use of hydrogen is in the production of the nitrogen compound ammonia, which is a colorless gas with an irritating odor. Ammonia is used in cleaning products, and can be used as a source of nitrogen for plants. About 25% of ammonia is converted into nitric acid, which is used to produce explosives, dyes and solid fertilizers. Artists use nitric acid to etch designs into metal plates. Some nitrogen compounds are extremely unstable.
7.3 Properties of d-block and f-block Element
- As you move across a period, (horizontal), the elements become harder, and require higher temperatures to melt and boil. Until you reach chromium. Chromium is the hardest. As you move right of chromium the electrons begin to pair up instead of standing alone. This makes them softer as you degrade. Zinc is the softest. (Because its "3d" orbitals are completely filled.)
- Electrons in d sublevels can absorb visible light of specific wavelengths. This results in colorful properties.
- Ferromagnetic are permanently aligned in the direction of a magnetic field because all ions are aligned in the same direction. Which means they have no opposite attractions to cancel out. (Iron, cobalt and nickel.)
- Strategic metals are metals that are essential for industry and national security, but for which a nation has little or no domestic supply. This list includes, but is not limited to platinum, chromium, cobalt, maganese, and tungsten. These transitional-strategic metals are rare because they are found combined in nature with other elements and require extensive procedures to extract them to their pure form.
- Lanthanide metals have "silvery" properties.
7.2 Properties of p-Block Elements